Abstract

GOMEZ-MANZO, Saúl; ARREGUIN-ESPINOSA, Roberto; CONTRERAS-ZENTELLA, Martha  and  ESCAMILLA-MARVAN, Edgardo. The alcohol quinoproteins dehydrogenases in the bacterial systems: distribution, classification, structure and function. TIP [online]. 2005, vol.8, n.1, pp.28-37. ISSN 1405-888X.

Microbial alcohol oxidoreductases constitute a very diverse group. They can be divided into three major categories. (a) NAD(P)-dependent dehydrogenases. (b) NAD(P)-independent enzymes that use pirroloquinoline quinone (PQQ), heme C as cofactor. (c) FAD-dependent oxidases that catalyze an essentially irreversible oxidation of alcohols. The ADHs that have PQQ as the prosthetic group are divided into 3 groups; types I, II and III. Type I ADH is a simple quinoprotein having PQQ as the prosthetic group; while type II and type III ADHs are quinohemoprotein having heme C as well as PQQ. Type II are soluble periplasmic enzymes and are widely distributed in Proteobacterias such as Pseudomonas putida, Ralstonia eutropha and Comamonas testosteroni. Type III ADHs are membrane-bound enzymes and oriented towards the periplasmic surface. They have been identified and characterized solely in acetic acid bacteria. Type III ADH consists of three subunits. The intramolecular electron transfer in the type II and III ADHs is the PQQ to heme C of the first subunit and there, from heme to heme in the second subunit until arriving at ubiquinone. The three types of PQQ-ADHs are discussed in this paper.

Keywords : Alcohol dehydrogenases (ADHs); pyrroloquinoline-quinone (PQQ); quinohemeprotein alcohol dehydrogenase (qhADH); quinohemeprotein ethanol deshydrogenase (qhEDH); quinoprotein ethanol dehydrogenase (QEDH); quinoprotein methanol dehydrogenase (QMDH).

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